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| United States Patent |
5,308,706
|
|
Kawaguchi
, et al.
|
May 3, 1994
|
Heat reflecting sandwich plate
Abstract
Disclosed herein is a heat reflecting sandwich plate made up of a first and
a second transparent plates bonded together with a transparent resin film.
The first transparent plate is coated on the inside thereof with a heat
reflecting film which is a laminate composed of two metal oxide layers,
with a noble metal layer intervening between them. The noble metal layer
has a sheet resistance of 4-10 ohms/square. The first and second metal
oxide layers have thicknesses controlled such that their ratio is in the
range of 1.1 to 1.6. The heat reflecting sandwich plate produces reflected
rays which have a chromaticness specified by -1.ltoreq.a.ltoreq.1 and
-1.ltoreq.b.ltoreq.1, where a and b denote the chromaticness indices of
Hunter's color specification system, and has a visible light reflectivity
lower than 10%. Because of these characteristic properties, the heat
reflecting sandwich plate has high strength and safety, exhibits
outstanding heat reflecting performance, and assumes almost no color and
looks good despite its comparatively high visible light transmittance.
| Inventors:
|
Kawaguchi; Jun (Yokohama, JP);
Hyodo; Tatsuya (Maizuru, JP);
Miyazaki; Takaharu (Maizuru, JP)
|
| Assignee:
|
Nippon Sheet Glass Co., Ltd. (JP)
|
| Appl. No.:
|
006173 |
| Filed:
|
January 15, 1993 |
Foreign Application Priority Data
| Jul 27, 1988[JP] | 63-99449 |
| Jul 07, 1989[JP] | 1-176725 |
| Current U.S. Class: |
428/426; 428/432; 428/437; 428/469; 428/623; 428/626; 428/630; 428/689; 428/925 |
| Intern'l Class: |
B32B 015/04; B32B 017/06; B32B 017/10 |
| Field of Search: |
428/426,432,437,469,623,626,630,689,925
|
References Cited
U.S. Patent Documents
| 3660137 | May., 1972 | Furuuchi et al. | 428/432.
|
| 4017661 | Apr., 1977 | Gillery | 428/412.
|
| 4160061 | Jul., 1979 | Okino et al. | 428/432.
|
| 4188452 | Feb., 1980 | Groth | 428/432.
|
| 4294881 | Oct., 1981 | Meyer et al. | 428/334.
|
| 4337990 | Jul., 1982 | Fan et al. | 350/312.
|
| 4382995 | May., 1983 | Lin | 428/415.
|
| 4497700 | Feb., 1985 | Groth et al. | 204/192.
|
| 4510190 | Apr., 1985 | Glaser | 428/34.
|
| 4600627 | Aug., 1986 | Honda et al. | 428/441.
|
| 4687687 | Aug., 1987 | Terneu et al. | 428/34.
|
| 4716086 | Dec., 1987 | Gillery et al. | 428/630.
|
| 4799745 | Jan., 1989 | Meyer et al. | 350/1.
|
| 4834857 | May., 1989 | Gillery | 204/192.
|
| 4948677 | Aug., 1990 | Gillery | 428/432.
|
| 4965121 | Oct., 1990 | Young et al. | 428/432.
|
| 4968563 | Nov., 1990 | Thomas | 428/432.
|
Primary Examiner: Page; Thurman K.
Assistant Examiner: Hulina; Amy L.
Attorney, Agent or Firm: Woodcock Washburn Kurtz Mackiewicz & Norris
Parent Case Text
This is a continuation of application Ser. No. 708,093, filed May 24, 1991,
now abandoned, which is a continuation of Ser. No. 384,559, filed Jul. 24,
1989, now abandoned.
Claims
What is claimed is:
1. A heat reflecting sandwich plate, for use in a vehicle, consisting of a
first and a second transparent plates bonded together with a transparent
resin film and a heat reflecting film,
characterized in that the first transparent plate is coated on the inside
thereof with said heat reflecting film which intervenes between the first
transparent plate and the transparent resin film, said heat reflecting
film being a laminate consisting of a first metal oxide single-layer
structure, a noble metal layer, and a second metal oxide single-layer
structure formed consecutively on the inside of the first transparent
plate, said first and second metal oxide layers each being made of any of
tin oxide, indium oxide, tin oxide containing indium oxide, zinc oxide or
antimony oxide, said first and second metal oxide layers each having a
thickness in the range of 190 to 690 .ANG. and each having a refractive
index in the range of 1.9 to 2.1, and the first and second metal oxide
layers having thicknesses controlled such that their total thickness is
500-900 .ANG. and the ratio of the thickness of the first metal oxide
layer to the thickness of the second metal oxide layer or the ratio of the
thickness of the second metal oxide layer to the thickness of the first
metal oxide layer is in the range of 1.1 to 1.6,
the noble metal layer has a sheet resistance of 4-10 ohms/square and is
made of one or more than one member selected from gold, silver, copper,
palladium and rhodium,
and the heat reflecting sandwich plate produces reflected rays which have a
chromaticness specified by -1.ltoreq.a.ltoreq.1 and -1.ltoreq.b.ltoreq.1,
where a and b denote the chromaticness indices of Hunter's color
specification system, and having a visible light reflectivity lower than
10%.
2. A heat reflecting sandwich plate as claimed in claim 1, wherein the
first and second transparent plates are sheet glass.
3. A heat reflecting sandwich plate as claimed in claim 2, wherein the
ratio of the thickness of the first metal oxide layer to the thickness of
the second metal oxide layer or the ratio of the thickness of the second
metal oxide layer to the thickness of the first metal oxide layer is in
the range of 1.2 to 1.5.
4. A heat reflecting sandwich plate as claimed in claim 3, wherein the
noble metal layer is made of silver as the major constituent and a small
amount of at least one member selected from gold, copper, palladium, and
rhodium.
5. A heat reflecting sandwich plate as claimed in claim 3, wherein the
noble metal layer is made of silver.
6. A heat reflecting sandwich plate as claimed in claim 3, wherein the
transparent resin film is made of polyvinyl butyral.
7. A heat reflecting sandwich plate as claimed in any of claims 1, 2, 3, 4,
5, 6, 7, 8, or 9, which has a visible light transmittance higher than 80%
and a solar radiant energy transmittance lower than 75%.
8. A heat reflecting sandwich plate consisting of a first and a second
transparent plates bonded together with a transparent resin film and a
heat reflecting film, characterized in that:
the first transparent plate is coated on the inside thereof with said heat
reflecting film which intervenes between the first transparent plate and
the transparent resin film, said heat reflecting film being a laminate
consisting of a first metal oxide single-layer structure, a noble metal
layer, and a second metal oxide single-layer structure formed
consecutively on the inside of the first transparent plate,
said first and second metal oxide layers each being made of any of tin
oxide, indium oxide, tin oxide containing indium oxide, zinc oxide or
antimony oxide and said first and second metal oxide layers each having a
thickness in the range of 190 to 690 .ANG.,
the first and second metal oxide layers have thicknesses controlled such
that their total thickness is 500-900 .ANG. and the ratio of the thickness
of the first metal oxide layer to the thickness of the second metal oxide
layer or the ratio of the thickness of the second metal oxide layer to the
thickness of the first metal oxide layer is in the range of 1.2 to 1.5,
the first and second metal oxide layers each have a refractive index in the
range of 1.9 to 2.1,
the noble metal layer has a sheet resistance of 4-10 ohms/square, and
the heat reflecting sandwich plate produces reflected rays which have a
chromaticness specified by -1.ltoreq.a.ltoreq.1 and -1.ltoreq.b.ltoreq.1,
where a and b denote the chromaticness indices of Hunter's color
specification system, and having a visible light reflectivity lower than
10%.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention:
The present invention relates to a sandwich plate composed of a pair of
transparent plates such as glass, synthetic resin or the like, and a
transparent interlayer of synthetic resin, said sandwich plate being
rendered capable of heat reflection. The heat reflecting sandwich plate is
suitable as vehicle and building window glass.
2. Description of the Prior Art:
There has been known sandwich glass made up of a pair of glass sheets (made
by, for example, float process) bonded together with an interlayer of
transparent synthetic resin such as polyvinyl butyral. The sandwich glass
of such multilayered structure has high strength and safety owing to the
interlayer's ability to prevent the glass plates from shattering in the
event of breakage.
A disadvantage of the sandwich glass used as vehicle and building window
glass is that it transmits a large amount of solar radiant energy into the
vehicle and building, causing the room temperature to rise unnecessarily,
particularly in summer.
There is disclosed in U.S. Pat. No. 4,337,990 a heat reflecting glass
prepared by forming a first metal oxide layer, a noble metal layer, and a
second metal oxide layer consecutively on a glass sheet. The first and
second metal oxide layers have almost the same thickness so that the three
layers give rise to, by their light interference, a low reflectivity for
light of wavelength 550 nm(nanometer) having a high visual sensitivity and
yet give rise to a high transmittance for visible light.
The heat reflecting glass disclosed in the above-mentioned U.S. Patent
gives a reflective spectrum which indicates the strong reflection in the
longer (red) side and shorter (blue) side of the visible region. This
spectral characteristic causes the heat reflecting glass to produce a
dazzling reflected ray of purplish color for the incident rays on either
sides. Because of this colored reflected rays, the heat reflecting glass
as vehicle and building window glass is out of harmony with the exterior
of the vehicle and building.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a heat reflecting
sandwich plate which has high strength, high safety (ability to prevent
shattering in the event of breakage), outstanding performance of heat
reflection, and comparatively high transmittance for visible light, and
yet looks good and takes on almost no color.
The present invention provides a heat reflecting sandwich plate made up of
a first and a second transparent plates such as glass, synthetic resin or
the like, bonded together with a transparent resin film, characterized in
that the first transparent plate is coated on the inside thereof with a
heat reflecting film which intervenes between the first transparent plate
and the transparent resin film, said heat reflecting film being a laminate
composed of a first metal oxide layer, a noble metal layer, and a second
metal oxide layer formed consecutively on the inside of the first
transparent plate, and the first and second metal oxide layers having
thicknesses controlled such that their total thickness is 500-900 .ANG.
and the ratio of the thickness of the first metal oxide layer to the
thickness of the second metal oxide layer or the ratio of the thickness of
the second metal oxide layer to the thickness of the first metal oxide
layer is in the range of 1.1 to 1.6, preferably 1.2 to 1.5, the noble
metal layer has a sheet resistance of 4-10 ohms/square, and the heat
reflecting sandwich plate produces reflected rays which have a
chromaticness specified by -1.ltoreq.a.ltoreq.1 and -1.ltoreq.b.ltoreq.1,
where a and b denote the chromaticness indices of Hunter's color
specification system, and has a visible light reflectivity lower than 10%.
According to the present invention, the noble metal layer is required to
have a sheet resistance of 4-10 ohms/square for the reason mentioned
below. With a sheet resistance smaller than 4 ohms/square, the noble metal
layer produces such a striking chromaticness on account of its excessively
high visible light reflectance that the reflected rays from the sandwich
plate has a chromaticness whose "a" and "b" are outside the range
specified above. Conversely, with a sheet resistance greater than 10
ohms/square, the noble metal layer does not reflect heat rays consistently
and tends to decrease in visible light transmittance on account of its
oxidation. In the case where the noble metal layer is made of silver and
has a sheet resistance of 4 ohms/square, it would have a thickness of 130
to 270 .ANG., depending on the method of preparation. With a sheet
resistance of 10 ohms/square, it would have a thickness of 60 to 150
.ANG., depending on the method of preparation. Therefore, the noble metal
layer may be 60-270 .ANG. thick if it is made of silver or a silver alloy.
According to the present invention, the first and second transparent plates
should preferably be sheet glass made by, for example, float process. They
may be properly colored according to need so long as they have a visible
light transmittance required. In addition, they may have any desired
thickness according to applications; but the adequate thickness is in the
range of 0.5 to 5 mm, preferably 1 to 3 mm.
According to the present invention, the first and second metal oxide layers
have thicknesses which are controlled such that their total thickness is
500-900 .ANG. and the ratio of the thickness of the first metal oxide
layer to the thickness of the second metal oxide layer or the ratio of the
thickness of the second metal oxide layer to the thickness of the first
metal oxide layer is in the range of 1.1 to 1.6. These requirements are
essential for the heat reflecting sandwich plate to produce reflected rays
which have a chromaticness specified by -1.ltoreq.a.ltoreq.1 and
-1.ltoreq.b.ltoreq.1, where a and b denote the chromaticness indices of
Hunter's color specification system. Thus, the sandwich plate takes on a
quiet color.
According to the present invention, the first and second metal oxide layers
each may have a refractive index in the range of 1.9 to 2.1 and a
thickness in the range of 190 to 690 .ANG..
According to the present invention, the first and second metal oxide layers
each may be made of any of tin oxide, indium oxide, tin oxide-containing
indium oxide (referred to as ITO hereinafter), zinc oxide, or antimony
oxide. The two metal oxide layers may be made of the same oxide or
different oxides. Usually, the tin oxide is stannic oxide (SnO.sub.2), the
indium oxide is diindium trioxide (In.sub.2 O.sub.3), the zinc oxide is
zinc oxide (ZnO) free of zinc suboxide, and the antimony oxide is
diantimony pentoxide (Sb.sub.2 O.sub.5) .
According to the present invention, the noble metal layer may be made of
one or more than one member selected from gold, silver, copper, palladium,
and rhodium. Preferable among them is silver because of its low visible
ray absorption. It is desirable that silver be used in combination with a
small amount of at least one member selected from gold, copper, palladium,
and rhodium, because silver alone lacks sufficient chemical resistance
such as moisture resistance, alkali resistance, and arid resistance. The
amount of gold and copper should preferably be less than 2% and the amount
of palladium and rhodium should preferably be less than 1%, and in the
case where two or more kinds of minor noble metals are used, their total
amount should be less than 2%; otherwise, the minor noble metal changes
the color of the noble metal layer made of silver alone, decreasing the
visible light transmittance. The noble metal layer should preferably have
a thickness in the range of 30 to 300 .ANG..
According to the present invention, the transparent resin film may be made
of any material so long as it is transparent in the visible region, has
almost the same refractive index as that of the transparent plate (about
1.52 in the case of sheet glass), and has good adhesion to both the
transparent plates and the heat reflecting film. An example of the
transparent resin film is the one made of polyvinyl alcohol resin (such as
polyvinyl butyral), vinyl acetate resin (such as ethylene vinyl acetate),
thermoplastic polyurethane resin, or polyvinyl chloride resin. Polyvinyl
butyral film is preferable. The film thickness may be in the range of 0.05
to 0.4 mm, preferably 0.1 to 0.2 mm.
According to the present invention, the heat reflecting sandwich plate
should preferably have a visible light transmittance higher than 80% and a
solar radiant energy transmittance lower than 75%, so that it permits the
sufficient transmission of visible light and yet cuts off a certain amount
of solar radiant energy.
The heat reflecting sandwich plate of the present invention may be produced
in the following manner. On the inside of the first glass plate are formed
the first metal oxide layer, the noble metal layer, and the second metal
oxide layer consecutively. The first glass plate, the transparent resin
film (in the form of sheet), and the second glass plate are laminated one
top after another. The resulting laminate is heated at
130.degree.-180.degree. C. under a pressure of 1-5 kg/cm.sup.2, so that
the transparent resin film is fusion-bonded to the second metal oxide
layer on the first glass plate and also to the inside of the second glass
plate. The laminate is cut to desired size and shape.
Where the heat reflecting sandwich plate of the present invention is used
as vehicle and building window glass, it is usually mounted such that the
first transparent plate (on which the heat reflecting film is coated)
faces outside. The thus mounted heat reflecting sandwich plate reflects
light on both sides, the reflected rays assuming substantially the same
chromaticness. Since vehicles and buildings are usually bright outside and
dark inside, the reflected light is a matter of concern when viewed from
outside and the transmitted light is a matter of concern when viewed from
inside. The heat reflecting sandwich plate of the present invention gives
almost colorless reflected light and transmits visible light sufficiently.
The heat reflecting sandwich plate of the present invention has a high
strength and is hard to break, because it is of multilayered structure
composed of the first transparent plate (on which the heat reflecting film
is coated), and the second transparent plate which are bonded together
with the transparent resin film.
The heat reflecting sandwich plate of the present invention prevents
shattering and hence secures great safety because the first and second
transparent plates are bonded together with the transparent resin film, so
that, when broken, the transparent plates tend to adhere to the resin film
rather than fly.
According to the present invention, the heat reflecting film coated on the
inside of the first transparent plate is composed of two metal oxide
layers and one noble metal layer intervening between them. The two metal
oxide layers have thicknesses which are controlled such that their total
thickness is in the range of 500 to 900 .ANG., with their ratio being 1.1
to 1.6. The sandwich plate produces reflected rays which have a
chromaticness specified by -1.ltoreq.a.ltoreq.1 and -1.ltoreq.b.ltoreq.1,
where a and b denote the chromaticness indices of Hunter's color
specification system, and has a visible light reflectivity lower than 10%.
Thus, the present invention provides a heat reflecting sandwich plate
which exhibits good performance of heat reflection and permits a
comparatively high visible light transmittance, and yet assumes almost no
color and looks good.
The above and other objects, features, and advantages of the present
invention will be readily understood by the following detailed description
in conjunction with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
The single drawing is a partial longitudinal sectional view showing the
heat reflecting sandwich plate of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A glass plate 10 (for example 2.1 mm thick) was coated with a first metal
oxide layer (for example 238 .ANG. thick) 11 of ITO (which is tin oxide
containing indium oxide composed of 10% tin oxide and 90% indium oxide,
the same shall apply hereinafter) by sputtering. The sputtering was
carried out in an atmosphere composed of argon and oxygen at a pressure
of, for example, 0.4 Pa (Pascal [neuton/m.sup.2 ]), using a sintered body
composed of tin oxide and indium oxide as the target. The first metal
oxide layer 11 was further coated with a noble metal layer 12 of silver
having a sheet resistance of 9 ohms/square by sputtering. The sputtering
was carried out in an argon atmosphere at a pressure of, for example, 0.4
Pa, using silver as the target. The noble metal layer 12 was further
coated with a second metal oxide layer (for example, 262 .ANG. thick) 13
of ITO by sputtering. The sputtering was carried out in an atmosphere
composed of argon and oxygen at a pressure of, for example, 0.4 Pa, using
a sintered body composed of tin oxide and indium oxide as the target. On
the second metal oxide layer 13 were laminated a, for example, 0.15 mm
thick transparent resin film of polyvinyl butyral 14 and a, for example,
2.1 mm thick glass plate 15 on top after another. The resulting laminate
was heated at, for example, 150.degree. C. and pressed under a pressure
of, for example, 3 kg/cm.sup.2 so that the polyvinyl butyral film 14 was
fusion-bonded to the second metal oxide layer 13 on the glass plate 10 and
also to the glass plate 15. The laminated product was trimmed to desired
size. Thus there was obtained a transparent heat reflecting sandwich plate
as shown in the accompanying drawing.
Heat reflecting sandwich plates of the same structure as mentioned above
were prepared except that ITO for the first metal oxide layer 11 was
replaced by ZnO, ITO for the second metal oxide layer 13 was replaced by
ZnO or SnO.sub.2, and silver for the noble metal layer 12 was replaced by
Ag-0.5%Cu alloy or Ag-1%Au alloy. In addition, heat reflecting sandwich
plates of the same structure as mentioned above were prepared except that
the thicknesses of the first and second metal oxide layers 11 and 13 were
varied in the range of 200 to 540 .ANG. and the sheet resistance of the
noble metal layer 12 was varied in the range of 6 to 9 ohms/square.
Tables 1 to 12 given below show the performance of the heat reflecting
sandwich plates prepared in Examples of this invention as mentioned above.
Table 13 shows the performance of the heat reflecting sandwich plate
prepared in Comparative Example. In tables 1 to 13, Hunter Chroma. means
the chromaticness indices of Hunter's color specification system. The heat
reflecting sandwich plates shown in Tables 1 to 13 have the first metal
oxide layer 11, the noble metal layer 12, and the second metal oxide layer
13 which were made of the following materials.
______________________________________
Examples
Table 1 ITO / Ag / ITO
Table 3 ITO / Ag / ITO
Table 4 ITO / Ag / ITO
Table 5 ITO / Ag / ITO
Table 6 ITO / Ag / ITO
Table 7 ITO / Ag / ITO
Table 8 ITO / Ag / ITO
Table 9 ZnO / Ag / SnO.sub.2
Table 10 ZnO / Ag / ZnO
Table 11 ITO / Ag-0.5% Cu / ITO
Table 12 ITO / Ag-1% Au / ITO
Comparative Example
Table 13 ITO / Ag / ITO
______________________________________
TABLE 1
__________________________________________________________________________
(ITO/Ag/ITO)
Layer construction Ratio of Reflect-
Transmit-
Sheet re- Total thick-
thicknesses ance of
tance of
Transmit-
Thickness
sistance of
Thickness
ness of layers
of layers
Hunter
visible
visible
tance of
of layer (11)
layer (12)
of layer (13)
(11) and (13)
(11) and (13)
chroma.
light
light
solar rays
(.ANG.)
(.OMEGA./.quadrature.)
(.ANG.)
(.ANG.)
(.ANG.)
a b (%) (%) (%)
__________________________________________________________________________
238 9 262 500 1.1 0.9
-0.7
7.9 83.6 69.9
227 9 273 500 1.2 0.7
-0.5
7.9 83.5 69.8
217 9 283 500 1.3 0.7
-0.2
7.9 83.5 69.8
208 9 292 500 1.4 0.3
-0.2
7.9 83.5 69.8
200 9 300 500 1.5 0.7
-0.3
7.9 83.4 69.8
__________________________________________________________________________
TABLE 2
__________________________________________________________________________
(ITO/Ag/ITO)
Layer construction Ratio of Reflect-
Transmit-
Sheet re- Total thick-
thicknesses ance of
tance of
Transmit-
Thickness
sistance of
Thickness
ness of layers
of layers
Hunter
visible
visible
tance of
of layer (11)
layer (12)
of layer (13)
(11) and (13)
(11) and (13)
chroma.
light
light
solar rays
(.ANG.)
(.OMEGA./.quadrature.)
(.ANG.)
(.ANG.)
(.ANG.)
a b (%) (%) (%)
__________________________________________________________________________
262 9 238 500 1.1 0.9
-0.7
8.0 83.6 69.9
272 9 228 500 1.2 0.7
-0.5
8.2 83.5 69.8
283 9 217 500 1.3 0.7
-0.4
8.2 83.5 69.8
293 9 207 500 1.4 0.6
-0.4
8.3 83.4 69.8
300 9 200 500 1.5 0.7
-0.6
8.4 83.4 69.8
__________________________________________________________________________
TABLE 3
__________________________________________________________________________
(ITO/Ag/ITO)
Layer construction Ratio of Reflect-
Transmit-
Sheet re- Total thick-
thicknesses ance of
tance of
Transmit-
Thickness
sistance of
Thickness
ness of layers
of layers
Hunter visible
visible
tance of
of layer (11)
layer (12)
of layer (13)
(11) and (13)
(11) and (13)
chroma.
light
light
solar rays
(.ANG.)
(.OMEGA./.quadrature.)
(.ANG.)
(.ANG.)
(.ANG.)
a b (%) (%) (%)
__________________________________________________________________________
429 9 471 900 1.1 0.1 -0.9
7.8 84.7 72.5
409 9 491 900 1.2 0.0 -0.7
7.8 84.6 72.4
391 9 509 900 1.3 0.0 -0.7
8.0 84.4 72.3
375 9 525 900 1.4 0.0 -0.7
8.0 84.4 72.3
360 9 540 900 1.5 -0.1
-0.7
8.3 84.4 72.3
__________________________________________________________________________
TABLE 4
__________________________________________________________________________
(ITO/Ag/ITO)
Layer construction Ratio of Reflect-
Transmit-
Sheet re- Total thick-
thicknesses ance of
tance of
Transmit-
Thickness
sistance of
Thickness
ness of layers
of layers
Hunter visible
visible
tance of
of layer (11)
layer (12)
of layer (13)
(11) and (13)
(11) and (13)
chroma.
light
light
solar rays
(.ANG.)
(.OMEGA./.quadrature.)
(.ANG.)
(.ANG.)
(.ANG.)
a b (%) (%) (%)
__________________________________________________________________________
471 9 429 900 1.1 0.1 -0.8
8.0 84.7 72.5
410 9 490 900 1.2 0.1 -0.4
8.2 84.5 72.3
509 9 391 900 1.3 0.0 -0.4
8.5 84.4 72.3
376 9 524 900 1.4 0.0 -0.1
8.6 84.0 72.1
540 9 360 900 1.5 -0.2
-0.1
9.0 83.9 72.1
__________________________________________________________________________
TABLE 5
__________________________________________________________________________
(ITO/Ag/ITO)
Layer construction Ratio of Reflect-
Transmit-
Sheet re- Total thick-
thicknesses ance of
tance of
Transmit-
Thickness
sistance of
Thickness
ness of layers
of layers
Hunter
visible
visible
tance of
of layer (11)
layer (12)
of layer (13)
(11) and (13)
(11) and (13)
chroma.
light
light
solar rays
(.ANG.)
(.OMEGA./.quadrature.)
(.ANG.)
(.ANG.)
(.ANG.)
a b (%) (%) (%)
__________________________________________________________________________
321 6 354 675 1.1 0.9
0.7
8.1 82.5 66.8
307 6 368 675 1.2 0.8
0.6
8.1 82.3 66.7
293 6 382 675 1.3 0.8
0.6
8.2 82.3 66.6
281 6 394 675 1.4 0.6
0.4
8.2 82.2 66.6
270 6 405 675 1.5 0.7
0.5
8.4 82.0 66.5
__________________________________________________________________________
TABLE 6
__________________________________________________________________________
(ITO/Ag/ITO)
Layer construction Ratio of Reflect-
Transmit-
Sheet re- Total thick-
thicknesses ance of
tance of
Transmit-
Thickness
sistance of
Thickness
ness of layers
of layers
Hunter
visible
visible
tance of
of layer (11)
layer (12)
of layer (13)
(11) and (13)
(11) and (13)
chroma.
light
light
solar rays
(.ANG.)
(.OMEGA./.quadrature.)
(.ANG.)
(.ANG.)
(.ANG.)
a b (%) (%) (%)
__________________________________________________________________________
353 6 322 675 1.1 0.9
0.7
8.4 82.5 66.8
368 6 307 675 1.2 0.8
0.6
8.5 82.3 66.7
380 6 295 675 1.3 0.8
0.6
8.7 82.3 66.6
395 6 280 675 1.4 0.6
0.4
8.9 82.2 66.6
406 6 269 675 1.5 0.7
0.4
9.3 82.0 66.5
__________________________________________________________________________
TABLE 7
__________________________________________________________________________
(ITO/Ag/ITO)
Layer construction Ratio of Reflect-
Transmit-
Sheet re- Total thick-
thicknesses ance of
tance of
Transmit-
Thickness
sistance of
Thickness
ness of layers
of layers
Hunter
visible
visible
tance of
of layer (11)
layer (12)
of layer (13)
(11) and (13)
(11) and (13)
chroma.
light
light
solar rays
(.ANG.)
(.OMEGA./.quadrature.)
(.ANG.)
(.ANG.)
(.ANG.)
a b (%) (%) (%)
__________________________________________________________________________
417 6 458 875 1.1 0.8
-1.0
8.2 83.0 68.2
398 6 477 875 1.2 0.6
-0.7
8.3 82.7 68.0
380 6 495 875 1.3 0.6
-0.7
8.4 82.7 67.9
365 6 510 875 1.4 0.3
-0.6
8.5 82.5 67.8
350 6 525 875 1.5 0.4
-0.7
8.8 82.1 67.6
__________________________________________________________________________
TABLE 8
__________________________________________________________________________
(ITO/Ag/ITO)
Layer construction Ratio of Reflect-
Transmit-
Sheet re- Total thick-
thicknesses ance of
tance of
Transmit-
Thickness
sistance of
Thickness
ness of layers
of layers
Hunter
visible
visible
tance of
of layer (11)
layer (12)
of layer (13)
(11) and (13)
(11) and (13)
chroma.
light
light
solar rays
(.ANG.)
(.OMEGA./.quadrature.)
(.ANG.)
(.ANG.)
(.ANG.)
a b (%) (%) (%)
__________________________________________________________________________
458 6 417 875 1.1 0.8
-0.9
8.4 83.0 68.2
475 6 400 875 1.2 0.6
-0.6
8.6 82.9 68.0
495 6 382 875 1.3 0.5
-0.5
9.0 82.7 67.9
510 6 365 875 1.4 0.2
-0.2
9.2 82.5 67.8
525 6 350 875 1.5 0.3
-0.1
9.7 82.1 67.6
__________________________________________________________________________
TABLE 9
__________________________________________________________________________
(ZnO/Ag/SnO.sub.2)
Layer construction Ratio of Reflect-
Transmit-
Sheet re- Total thick-
thicknesses ance of
tance of
Transmit-
Thickness
sistance of
Thickness
ness of layers
of layers
Hunter
visible
visible
tance of
of layer (11)
layer (12)
of layer (13)
(11) and (13)
(11) and (13)
chroma.
light
light
solar rays
(.ANG.)
(.OMEGA./.quadrature.)
(.ANG.)
(.ANG.)
(.ANG.)
a b (%) (%) (%)
__________________________________________________________________________
238 8 262 500 1.1 0.9
-0.9
7.9 83.0 67.7
227 8 273 500 1.2 0.7
-0.2
8.0 83.6 67.5
217 8 283 500 1.3 0.6
-0.2
7.9 83.7 67.3
208 8 292 500 1.4 0.7
-0.3
8.0 83.6 67.4
200 8 300 500 1.5 0.8
-0.3
8.0 83.6 67.5
__________________________________________________________________________
TABLE 10
__________________________________________________________________________
(ZnO/Ag/ZnO)
Layer construction Ratio of Reflect-
Transmit-
Sheet re- Total thick-
thicknesses ance of
tance of
Transmit-
Thickness
sistance of
Thickness
ness of layers
of layers
Hunter
visible
visible
tance of
of layer (11)
layer (12)
of layer (13)
(11) and (13)
(11) and (13)
chroma.
light
light
solar rays
(.ANG.)
(.OMEGA./.quadrature.)
(.ANG.)
(.ANG.)
(.ANG.)
a b (%) (%) (%)
__________________________________________________________________________
240 7 260 500 1.1 0.9
-0.8
8.0 83.6 67.9
230 7 270 500 1.2 0.7
-0.4
8.0 83.6 67.8
220 7 280 500 1.3 0.7
-0.2
8.2 83.7 67.8
210 7 290 500 1.4 0.6
-0.3
8.3 83.8 67.7
200 7 230 500 1.5 0.8
-0.4
8.5 83.8 67.6
__________________________________________________________________________
TABLE 11
__________________________________________________________________________
(ITO/Ag-0.5% Cu/ITO)
Layer construction Ratio of Reflect-
Transmit-
Sheet re- Total thick-
thicknesses ance of
tance of
Transmit-
Thickness
sistance of
Thickness
ness of layers
of layers
Hunter
visible
visible
tance of
of layer (11)
layer (12)
of layer (13)
(11) and (13)
(11) and (13)
chroma.
light
light
solar rays
(.ANG.)
(.OMEGA./.quadrature.)
(.ANG.)
(.ANG.)
(.ANG.)
a b (%) (%) (%)
__________________________________________________________________________
286 9 314 600 1.1 0.8
-0.5
8.0 82.6 68.5
272 9 328 600 1.2 0.7
-0.3
8.0 82.5 68.5
261 9 339 600 1.3 0.5
-0.3
8.0 82.5 68.5
250 9 350 600 1.4 0.6
-0.3
8.1 82.4 68.4
240 9 360 600 1.5 0.7
-0.4
8.2 82.4 68.4
__________________________________________________________________________
TABLE 12
__________________________________________________________________________
(ITO/Ag-1%Au/ITO)
Layer construction Ratio of Reflect-
Transmit-
Sheet re- Total thick-
thicknesses tance of
tance of
Transmit-
Thickness
sistance of
Thickness
ness of layers
of layers
Hunter
visible
visible
tance of
of layer (11)
layer (12)
of layer (13)
(11) and (13)
(11) and (13)
chroma.
light
light
solar rays
(.ANG.)
(.OMEGA./.quadrature.)
(.ANG.)
(.ANG.)
(.ANG.)
a b (%) (%) (%)
__________________________________________________________________________
290 9 310 600 1.1 0.9
-0.8
8.0 83.2 68.6
270 9 330 600 1.2 0.6
-0.5
8.1 83.1 68.5
262 9 338 600 1.3 0.5
-0.5
8.2 82.6 68.5
250 9 350 600 1.4 0.2
-0.5
8.2 82.6 68.4
240 9 360 600 1.5 0.3
-0.5
8.2 82.6 68.4
__________________________________________________________________________
TABLE 13
__________________________________________________________________________
(comparative example - ITO/Ag/ITO)
Layer construction Ratio of Reflect-
Transmit-
Sheet re- Total thick-
thicknesses ance of
tance of
Transmit-
Thickness
sistance of
Thickness
ness of layers
of layers
Hunter
visible
visible
tance of
of layer (11)
layer (12)
of layer (13)
(11) and (13)
(11) and (13)
chroma.
light
light
solar rays
(.ANG.)
(.OMEGA./.quadrature.)
(.ANG.)
(.ANG.)
(.ANG.)
a b (%) (%) (%)
__________________________________________________________________________
450 9 450 900 1.0 1.1
-1.2
8.3 83.1 68.2
__________________________________________________________________________
Tables 1 to 13 indicate the following.
(1) In Comparative Example shown in Table 13, the heat reflecting sandwich
plate gives the Hunter chromaticness "a" and "b" whose absolute values are
greater than 1, because the first metal oxide layer (11) and the second
metal oxide layer (13) have such thicknesses that their ratio is 1.0.
(2) In Examples of this invention shown in Table 1 to 12, the heat
reflecting sandwich plates give the Hunter chromaticness "a" and "b" whose
absolute values are smaller than 1. In the case where the ratio of the
thicknesses of the first and second metal oxide layers 11 and 13 is in the
range of 1.2 to 1.5, the heat reflecting sandwich plate gives the Hunter
chromaticness "a" and "b" whose absolute value are sufficiently smaller
than 1, compared with the case in which the ratio is 1.1.
Therefore, the heat reflecting sandwich plate in Comparative Example shown
in Table 13 gives dazzling reflected light of purplish color, as mentioned
above as prior art, whereas those in Examples of this invention shown in
Tables 1 to 12 give almost colorless reflected light and hence look good.
Having described illustrative embodiments of the invention with reference
to the accompanying drawing, it is to be understood that the invention is
not limited to such precise embodiments, and that various changes and
modifications may be effected therein by one skilled in the art without
departing from the scope and spirit of the invention as defined in the
appended claims.
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